We performed a large series of experiments starting 3 years ago using GFP bone marrow transplanted mice that underwent brain surgery (middle cerebral artery occlusion ? MCAO; stroke). Following surgery we used different growth factors injected locally; peripheral bone marrow stimulation; and a combination of the above to study the possible role of circulating bone marrow cells in CNS regeneration after stroke. We performed behaviour tests at different time points; injected growth factors into the stroke site; perfused all (60) mice; saved all organs. We have been sectioning and evaluating the brains following multiple immunostainings and in situ hybridizations ? in correlation with the motor tests. In collaboration with Denis Faustman and Simon Tran we are analyzing the salivary glands of NOD mice that received healthy gender mismatched bone marrow. We are trying to correlate the number of newly formed salivary (secretory) cells that originate in the BM with salivary function. We are trying to see if a healthy BM (that does not have the genetic problem of the NOD mice) would be able to rescue the salivary glands of these mice. Bob Redman has been trying to inject gender mismatched BM into the salivary ducts of rats in order to see if these cells can be incorporated into the gland; could function as secretory cells and if their number will increase following injury to the gland. We have been working with him on trying to set up the technique to detect the Y chromosome in the glands and to be able to double label it with salivary cell markers (such as cytokeratin; cadherin; mucin). The rat Y chromosome detection is much more difficult than the mouse due to the lack of a repeat sequence that is specific to the Y. Once the technique works we will study the differentiation potential of different populations of BM cells. In collaboration with Andras Bratincsak, and Michael Brownstein (NIMH) we developed a transgenic mouse (CRE-CD45) model that enables us to track cells of the hematopoetic line to study their fate choices. We have now crossed this mouse with an EGFP-Lox mouse and in the resulting offsprings all cells that ever expressed CD-45 (a considered hematopoetic cell marker) will recombine the DNA in a way that they will express GFP no matter what tissue they end up in. Using this model we will be able to study the specific contribution of hematopoetic cells to other organs in health and in disease.